Explore and develop the use of argon laser in the oral cavity, including the prevention or reduction of tooth decay, polymerized restorative materials, and periodontal surgery. The potential usefulness of lasers to prevent decay-like lesions in vitro has been reported and other applications are being investigated. Animal and clinical trials need to be conducted, but first, the biological safety parameters need to be established. We propose to establish for the argon laser the power density limits (joules/cm2) at which point damage or potential damage begins to occur to dental pulp and enamel as a result of the laser. These limits will be established through pulp histology studies, pulp temperature studies, and enamel surface studies using dogs' teeth in vivo, extracted human teeth, standard histology and S.E.M. techniques. The laser power will be increased by controlled increments until thresholds are reached and safety ranges established. The correlation of results from these studies will allow us to proceed with the planning of animal and clinical studies within the defined limits of safety to avoid damage to the pulp and/or enamel.